1. Field of the Invention
The present invention relates generally to filters, and in particular to a cartridge filter for filtering dust and other airborne particulates from an air stream with a porous media element.
2. Description of the Prior Art
Particulate filter systems comprise a common type of environmental control equipment. A typical particulate filter system includes a porous media element for passing a gaseous stream therethrough and trapping particles entrained in the gaseous stream.
Air quality issues are addressed by both Occupational Safety and Health Administration (OSHA) and Environmental Protection Agency (EPA) regulations. OSHA regulations address air quality in the workplace, and EPA regulations address particulate emissions to the atmosphere. The general trend with such regulations over the last few decades is towards greater restrictiveness, i.e. requiring manufacturers and other producers of airborne particulates to filter out increasingly high levels of the particulates. Moreover, production facilities are often operated at production levels close to their maximum capacities in order to maximize the efficient use of available resources. Increased production often creates increased levels of particulate emissions, which must be effectively filtered before discharge to the atmosphere.
Filter systems known as baghouses are commonly used in industrial applications for particulate filtering applications. Baghouse filter systems generally comprise large enclosures with media elements (e.g., bags) comprising porous materials which are placed in the paths of the gaseous exhaust streams. The media elements can comprise, for example, woven or nonwoven fabrics, cellulose-based materials such as paper, synthetics, or other materials. Spun bonded polyester has been successfully employed as the filter medium element in baghouse applications.
The media elements are preferably configured to maximize their exposure to the gaseous exhaust stream and to facilitate efficient installation and removal. Many filter systems include purge cycles in which particulates which have accumulated on the filter media are dislodged for disposal.
Cartridge filters are generally cylindrical in configuration with tubular media elements. To maximize the exposed media element surface areas, longitudinally-pleated media elements have been employed with the pleats providing greater exposed surface areas. In a typical installation, a number of cartridge filters are mounted on a tube sheet which separates the filter system housing into inlet and discharge compartments with the gaseous stream passing through the media elements as it exits the inlet compartment and enters the discharge compartment.
Problems have arisen with prior art cartridge filters in connection with their tube mounting assemblies, which mount the tubular media elements on the tube sheets. Various combinations of materials have previously been employed for manufacturing tube mounting assemblies, such as urethanes, EPDM, etc. Mechanical fasteners have also been utilized for attaching cartridge filters to tube sheets, and for attaching the different parts of tube mounting assemblies together. However, it is generally preferable to avoid metal fasteners and other metal parts to simplify production and to reduce problems associated with the disposal and/or recycling of used cartridge filters.
Heretofore there has not been available a cartridge filter with the advantages and features of the present invention.